The Endo Fix

Resorption Classification for Clinicians

Historically, classifying systems for resorption have been insufficient to adaquitely guide the treating doctor and inform decision making in the clinical management of resorption . Words like inflammatory and replacement as identifiers are less than ideal as all resorption is inflammatory and all resorption involves replacement.  Identifiers using cervical when used to describe ECIR are not really accurate either and are really misleading as the resorption typically stems from the level of the crestal bone. For these reasons, based on more current models, I use a clinical model of classifying resorption, and subsequent management thereof:

Hampton Endodontist, www.endovirginia.com

The initial identifiers are based first on the derived process location- either external or internal. It’s important to note that the identifiers are derived from imaging, most often CBCT imaging.

Internal Resorption is derived from the pulp. The presentation can be with either a vital or necrotic pulp. Additionally, the resorption can be further classified by extent- namely non-perforating, or perforating. Internal Resorption that is perforating may require surgery to adequately manage the case. Often the process involves a vital pulp, however, occasionally, the pulp may be non-vital. From a prevalence perspective, internal resorption is low; its rare. With internal resorption, since the process is pulpally derived, the replaced tissue is radiolucent. There is not a bone deposition component to internal resorption.

Internal resorption with a necrotic pulp:

Suffolk Endodontist

Internal Resorption with Perforation:

Tidewater Endodontist

External resorption refers to the process of tooth structure being removed and replaced from the outside. Additional identifiers depict distinctions based on a mix of location, cause, and extent. External Crestal Resorption is by far the most common type of resorption. It originates at the level of the crestal bone. A mix of soft granulomatous tissue and hard boney tissue invade and replace the tooth. Additional identifiers include scooping or tunneling. Scooping refers to the pattern of extension by which it progresses in a relatively bowled out fashion as if the tooth removal was performed with a small ice cream scoop. Tunneling refers to a thin fingerlike progression, often many of them progressing axially. Finally, the extent of the External Crestal Resorption may be described. Mild refers to external resorption that doesn’t involve the pulpal space. Moderate is likely to involve the pulp space and will require endodontic therapy. Severe resorption is the extent whereby the tooth is usually no longer restorable. The determination of restorability is made via CBCT. One thing to keep in mind when determining the extent of the resorption is the hard tissue component invading the tooth. It’s easy to mistake tooth schema for invading bone or bone schema. Additionally, the pdl is not present in this area making the distinction more difficult. Sometimes, changing the scale of the imaging during viewing can help. that’s because the process of interpreting schemata is itself dependent on scale. For example, we understand that mouth is part of face, and lips are part of mouth, and vermilian border part of lips. Changing the scale helps with understanding features at all levels.

External Crestal Resorption, Moderate Scooping:

Suffolk Endodontist

External Crestal Resorption, Severe, Tunneling:

Tunneling Resorption presents challenges as the osseous tissue embeds itself axially. Aggressive removal weakens the tooth, however, leaving bone behind allows for resorptive progression.

External Apical Resorption:

Chesapeake Endodontist

External Apical Resorption can be a result of orthodontic force, root canal infection, or in some cases, unknown causal relation.

 

 

External Pressure Resorption:

Chesapeake Endodontist

Teeth and expansile growths such as cysts can cause pressure resorption. Depending on the restorability the extent may be mild, moderate, or severe.

External Axial Resorption:

Hampton Roads Endodontics

External Axial Resorption is identifiable by the radiolucent areas adjacent to root structures. Often this is sequela of trauma and accompanied by an infected tooth. This resorption may be arrested by endodontic therapy and medication with calcium hydroxide. The extent of the injury and development of the tooth determines the prognosis. Often injuries to these teeth include avulsion, lateral luxation, intrusion or extrusion. Depending on the extent of External Axial Resorption, External Ankylotic Resorption may follow over time.

 

External Ankylotic Resorption:

Newport Bews Endodontist

External Ankylotic Resorption may follow after External Axial Resorption. The difference is the lack of radiolucent areas adjacent to the root. As with other external resorption where bone deposition is involved, distinguishing between root and bone schemas can be difficult. The appropriate interpretive response is increased uncertainty. In the developing adolescent, when facial development is not complete, the management of External Ankylotic Resorption is decoronation. An alternative might include autotransplantation if there is a knowledgeable and skilled surgeon.

 

 

External Resorption of a Lower Canine

External Resorption
Suffolk Endodontist
Newport news Endodontist

Lower canines seem to exhibit a higher degree of prevalence of external resorption than other teeth. Perhaps it’s the higher forces as they guide the occlusion. Perhaps it’s their position as the corner of the arch which. Perhaps its the periodontal treatments that these teeth undergo. Or maybe it’s something else. 3D imaging helps determine the restorability of these teeth. When the resorption passes two line angles most times I’ll throw in the towel. This was the case with the contralateral tooth. By way of clinical classfication this one was external moderate scooping resorption. As is always the case there is osseous in-growth. It’s important to remember that there is hard tissue replacement when reading the scan or the extent of the resorption may be underestimated. It’s important to remove the osseous ingrowth and resect it back until healthy periodontal ligament can be observed under the microscope. As is typical of these cases, the soft tissue looks good at 48 hours during the suture removal appointment.

Trauma, Resorption, and Decoronation

Suffolk Endodontist

This little guy caught a fly ball… in the mouth. The lateral was laterally luxated. The central was avulsed and replanted with a dry time of 15 minutes. The lateral was repositioned and splinted. I saw them the day after the injury. We made sure he was on an antibiotic and anti-inflammatory and saw him back in a week to start endodontic therapy as the apex of these teeth were completely deveoloped and the risk of resorption high. After what we thought was a sufficient time in both CaOH and splint therapy, we completed the endodontic therapy and placed fiber posts.

Newport News Endodontist

Over the next few years we saw resorption develop. According to the Resorption Classification for Clinicians, this resorption would be considered External Crestal Resorption, moderate scooping. We removed the invasive tissue and restored the root using composite. A custom resin matrix was used for isolation.

Hampton Roads Endodontist

Over time, we could see that the central was subject to resorption as well; External Ankylotic Resorption. This was evident by the ankylotic tone when percussed. Radiographically, this was evident my the marked lack of periodontal ligament and lack of tooth root definition. Clinically, this was evident by the infraposition of the clinical crown relative to the other central.

Root Canal Expert

In treatment planning the case, the orthodontist thought some initial leveling and aligning using the ankylosed tooth would be helpful before decoronation. After this was accomplished, the fiber post and root filling was removed and the crown was decoronated using the flapless decoronation approach as outlined by Jared Buck in Best Practices: A Desk Reference

Chesapeake Endodontist

A pontic was added to the orthodontic therapy.

Harbor View Endodontist

We can see over time that bone developed over the tooth root and the the root is turned over in osseous regeneration. The alveolar ridge is preserved for future restorative replacement.

Hampton Roads Endodontist

Here’s the 5 year followup.

Internal Approach

This tooth presented with inter-proximal external crestal resorption according to my resorption classification for clinicians. Usually I like to have an external surgical approach to ensure clean margins, manage the field, and work the appropriate matrix. However, an external approach here would have left one hell of a periodontal problem and lots of bone destruction. So, we worked it out internally. Ultimately, glass ionomer was used as the restorative choice here. On short termish recall, the perio tissues look great- 3mm probings all around and no bleeding on probing. So far so good, no resorptive recurrence.

Decoronation of an Ankylosed Tooth

Decisions…decisions. A very young looking 10 year old girl presented after an avulsion of tooth number 9 with a very short extra-oral dry time, immediately replanted and subsequently splinted. The decision of whether to initiate endo on the central is dictated by the time out of the mouth and the development of the tooth. I made the call that the apex looked wide open and the tooth hadn’t completely developed. So we decided to wait and see if the tooth would revascularize. My first follow-up time of trauma is typically 3 weeks. I saw her inside of 4 and resorption was already full on; progressive and aggressive. Classification wise this would be external axial resorption. We initiated endo immediately, but the damage was done. Additionally, the concussed lateral wasn’t responding to cold, so we started endo on that one as well.

We kept the tooth in medication for 5 months changing it out monthly. Over that period of time there was ankylotic tone and no mobility under the scope using 2 mirror handles to evaluate. Ugh. We placed Vitapex in the canal which lasts longer than many other CaOH preparations, and restored. Over time, washing out of the medication could be observed; a common finding in a resorbing root. We waited until we measured 3mm infra-occlusion and set her up for a flapless decoronation like my buddy Buck came up with circa 2008.

If you can, preserve the pulp. If you can’t; save the root and tooth. If you can’t do that, at least save the bone. That’s where decoronation comes in.

We clamped the other central and split dam to the distal of the lateral and used a rubber dam triangle to wedge the dam distally. Then we cut the crown off using a an 014 tapered diamond. Then a surgical length 556 on end, we cut the tooth flat to 1-2mm below the bone. It’s critical to remove all the enamel as it won’t resorb. We observed granulomatous soft tissue extending from the canal space. A good clot was evident before dismissing the patient.

Hindsight being 20/20 I woulda medicated the tooth at a week. Similar patient representing the same way? That’s tougher. I’m thinking if the tooth looks most of the way developed, regardless of the apex developement, I might jump in. It’s a tough call.